A significant cost factor in laser technology is the necessity to shield the operating region so as to be safe with respect to lasers. Conventionally, this is achieved by means of complex protective housings, robot cells, etc.
Moreover, there are laser welding head in which local shielding is produced itself by the laser welding head or components which are arranged thereon. The workpiece is clamped between two (upper and lower) clamping claws associated with the laser welding head or the components arranged thereon, and the laser beam is focused by welding optics onto the workpiece through a clamping claw opening of the upper clamping claw. The welding optics is movably supported in the laser welding head, which in turn is securely fixed to the upper clamping claw.
A funnel-like shaft between the laser welding head and the upper clamping claw acts as a protective housing for the laser beam. In addition, a cross jet is located in the protective housing in order to protect a protective glass pane which is located in front of the welding optics from splashes during the laser welding operation. The laser welding head and the upper clamping claw therefore form a unit which has to be disassembled, for example, in order to clean or replace the upper clamping claw. However, it is particularly disadvantageous in this construction that the clamping of the workpiece has to be carried out again for each welding portion since the clamping claw is directly coupled to the optics. This process is not only time-intensive but leads to positioning actions of the clamping claw and the optics outside a predetermined tolerance, in particular in conjunction with a robot—which in comparison is instead intended to be considered to be soft with respect to the rigidity—as a handling medium of the optics owing to limited positioning precision levels and/or other error sources.
The higher weight of the laser processing head as a result of the construction when the upper clamping claw is integrated exacerbates this problem or requires greater efforts to ensure the positioning precision. In addition, owing to the upper clamping claw which is secured to the optics as a protective housing, the spacing between the optics and workpiece is predetermined in the laser-safe state. If a focal point is intended to be changed with respect to the workpiece surface, this is intended to be solved by means of a focal point adjustment which is internal with respect to the optical unit and which is intended to be provided in the laser processing head. This also results in a comparatively increased weight with the disadvantages which have been described above.